This plugin adds up to four new buttons / links to the WordPress Editor panel. You can select to add a quicktag to easily insert: 
Amazon item links 
Amazon product searches 
custom span class 
custom div class
The settings pane allows you to enter defaults, as well as your own Amazon associate ID.

David’s Ultra Quicktags

Adds new buttons to the Editor window (Amazon Links, Amazon Search, etc.).

regen

This plugin inserts quicktags of the admin page to the upper part of textarea of the comment form.
<h4>Features</h4>
<ul>
<li>You can edit tags in the admin page.</li>
<li>You can limit quicktags by user roles.</li>
</ul>

Comment Form Quicktags

This plugin inserts a quicktag toolbar on the comment form.

David’s Ultra Quicktags vs Comment Form Quicktags